The increasing use of avionics, electrically powered subsystems, electric actuation systems (“EAS”), and the like, onboard commercial and military aerospace vehicles has led to a desire for improved thermal management of the heat loads produced by these electrical components. For example, aerospace vehicles with EAS, as opposed to hydraulically actuated control systems, are becoming more common. However, aerospace vehicles with EAS often include more actuators for ailerons, flaps, and other components, which produce more heat than comparable hydraulic actuators. Moreover, hydraulic actuation systems naturally transfer heat from their associated actuators by way of the hydraulic fluid, whereas EAS do not typically include such heat transfer systems.
Some current approaches to thermal management in aerospace vehicles are achieved with higher costs, possible reduction of overall component performance, decreased efficiency and/or increased weight. Effective management of thermal loads in aerospace vehicles is also affected by the trend toward the use of thermally conductive carbon fiber composites and other thermally conductive non-metallic materials for aircraft structural members and aircraft skin in order to reduce weight. Many common composite materials have lower thermal conductivity than metals, such as aluminum and, thus, while lighter they do not conduct away heat as efficiently. For certain military aerospace vehicles, there is also a desire to maintain smooth exterior surfaces with a minimum number of penetrations in order to increase stealth or other detection avoidance characteristics. This can further reduce the design options for managing thermal loads.
In addition, effective thermal management of electric components such as EAS is one of the greatest challenges for the More Electric Aircraft (MEA) due to, for example, limited heat sink capacity. Likewise, for future MEA aircraft using thinner wing cross sections, weight, size, and heat dissipation requirements will become even more challenging. Therefore, a structurally integrated actuation system and thermal management approach comprising load bearing actuators, new cooling techniques, and high-performance materials coupled with new packaging concepts is desirable.
In most existing systems, the EAS and other electric motors have been either liquid cooled or designed with sufficient metal to enhance its ability to provide a heat sink for the excessive heat that was generated during operation. Current MEA applications are not structurally integrated and either use a separate cooling loop that dumps heat into a fluid/air, or over-designs the electric motor and other various components to enhance their heat sinking capabilities. The use of a centralized coolant loop to handle the thermal load generated by distributed components entails increased system complexity, maintainability and concomitant weight and volume penalties.
Accordingly, there is a need for an improved cooling system for controlling heat loads generated by electrical components onboard aerospace vehicles. Other drawbacks with existing systems may also exist.